DMH Stallard has beaten 16 other firms to become the sole legal adviser for Shoreham Port.
DMH Stallard got through a three-stage process that lasted eight weeks and included a final round against DLA Piper and East Anglian boutique Prettys to represent the port for the next five years.
Shoreham Port is located just west of Brighton and comprises a 150-acre industrial site with more than 100 tenants and a large fishing fleet. It is in the middle of a £250m regeneration programme that will create more than 1,000 jobs for the local community.
Commercial property partner Marion Wilcock, who led the Shoreham pitch, said: "We sold ourselves as a one-stop shop for the port. We offer a good quality commercial property service that includes chartered town planners as well as lawyers and we can provide expert advice on the environmental concerns that affect ports."
Partners Tony Allen, Heidi Copland and Justin Ellis worked with Wilcock on the pitch. The firm also represents Newhaven Port & Properties.
Wilcock also led the team to scoop the position of reserve contractor for the City of Westminster, replacing Sharpe Pritchard.